Friday, January 29, 2010

It's been a rather frantic week, and I know there is a series on weight hanging in between Part 3 and Part 4. I'm hoping to get to that next week, when hopefully I'll have a little more time!

But today, I have to comment on this latest study, which I know will become bigger in the coming days - it is a new study that will reignite the barefoot vs. shoe debate, one of the more controversial issues in running.

I am actually planning a whole series on this topic, because I was recently interviewed by a Dutch Running magazine, Run2Day, and I'm going to post that entire interview (with additions) on the site at some point in February.

The scientists took five group of runners and had them run both barefoot and in shoes. The groups were: Habitually shod adults in the USA, Recently shod adults in Kenya, Habitually barefoot adults in the USA, Barefoot adolescents in Kenya, and Shod adolescents in Kenya.

Each group ran in shoes and barefoot and they measured foot-strike pattern (whether the runner lands on the heel, midfoot or forefoot) and kinematic and kinetic variables like impact force, loading rate, and joint angles.

The findings - a shift in landing, a reduction in force

It turns out that people who run barefoot, even when shifting from shoes to the barefoot condition (the habitually shod groups), shift the landing point to the forefoot. There's nothing new there - it's been known for many years that running barefoot changes the footstrike. Hundreds of studies exist to show this. The next difference is the ankle angle - the barefoot runner has a more plantarflexed ankle when they land - what this means is that the toe is pointed away from the body more (compared to dorsiflexion, when you pull it back towards you at the ankle). Again, hundreds of studies have shown this.

Next are the impact forces. Here's where there is some disagreement. Previous studies have occasionally disagreed on how barefoot running affects impact forces - some say it actually increases them, with high variability between individuals. Most suggest a reduction, particularly early on during impact (first impact). The Nature study has found that being barefoot AND landing on the forefoot reduces both the loading rate and the peak impact force. In fact, it's three times lower in barefoot runners who forefoot strike (which is most of them) than in heel strikers wearing shoes. In theory (though this too is disputed), higher impact forces and loading rates equals greater injury risk, and so the study is suggesting that perhaps people who are barefoot or minimally shod have a better chance of avoiding injury.

A stimulus plan for physical therapists and podiatrists?

And here is where it gets tricky. I must point out that the title of the paper is Foot strike patterns and collision forces in habitually barefoot versus shod runners. I highlight the word "habitually", because it's quite important to appreciate the impact that this word may have on how you apply this finding.

I guarantee that the media are going to be all over this and they are going to tell you that you should be running barefoot or in Vibrams. You will hear how science has proven that being barefoot will prevent injuries, and that those of you who are injured should blame your shoes as you lob them into the garbage bin.

None of these suggestions is true, yet. And Dan Lieberman who headed up this latest study would not even be suggesting this himself. The final sentence in the paper in fact reads "controlled prospective studies are needed to test the hypothesis that individuals who do not predominantly RFS either barefoot or in minimal footwear, as the foot apparently evolved to do, have reduced injury rates" (good science always recognizes what it DOESN'T say, and Lieberman and co fit this category).

What the Nature study hasn't measured is the long term (or even the short term) effects of the change on loading rates on different joints. If you wish to guarantee yourself an injury, then go out for a 2km run barefoot on a hard surface, and you will be asking your calf muscles and Achilles tendons to do work that for perhaps 30 years, they haven't had to do.

And I will illustrate this with our own insight into footstrike and injury. When the Pose research was done in Cape Town, athletes basically had their footstrike patterns changed through 2 weeks of training in the new method. The biomechanical analysis found lower impact forces (sound familiar? Same as the Nature paper), and even less work on the knee joint. This was hailed as a breakthrough against running injuries, because lower impact plus lower work on the knee meant less chance of injury. Jump ahead 2 weeks, and 19 out of 20 runners had broken down injured. Why? Because their calves and ankles were murdered by the sudden change. And the science showed this - the work on the ANKLE was significantly INCREASED during the forefoot landing.

The point is, changing how you run, whether by technique training or a change in shoes (like running barefoot) will load muscles that may be very weak, and joints and tendons well beyond their means. If however, you are a habitually barefoot runner, then you can do this, because your body has been prepared for it. For everyone else, I think we may be underestimating the time it will take to transition successfully to barefoot running (or forefoot striking, if you're going to force that change 'unnaturally').

And there is my point - taking this kind of interesting study, and dispensing advice, is a risky business. As a friend pointed out yesterday - the media's interpretation of this study will be a "stimulus plan for physical therapists and podiatrists". Going from years of shoes into minimal shoes or barefoot will injure you if you are not careful.

Conclusion

The Nature study provides a good discussion point. It's intriguing, and certainly does suggest advantages to barefoot running. It is not the last word, but rather the latest word in this debate. Nor is it revolutionary, because for many years, we've known that being barefoot changes ankle angle on impact, footstrike and loading rates (though quite how they change is not agreed upon).

I'm sure a lot more will be written - I'll even cover some of it when I do that interview series on this topic in the coming weeks. For now, that's the last I'll say on this particular issue, but debate is always welcome!

Ross

P.S. Daniel Lieberman has launched a website on this topic, and it's well worth a look. It is obviously based on his research (this study forms the bulk of it), but it's a good, clear explanation of the concepts. Again, the same word of caution applies - don't jump from one to the other. If there is one section of that website that you should read over and over, it is the Training tips section. Most will not, and they'll become the statistics (and the stimulus for physical therapy), but if you manage it right, then the site will be a great help to you!

Friday, January 22, 2010

2:06:09 can never be deemed a disappointing performance - it's a time that ten years ago would have scared the world record, been comfortably in the top 10 of all time, and would signal a great effort. It's testament to how the marathon has progressed, and to what Haile Gebrselassie has achieved in his running career, that when he achieves this time, it's met with some disappointment.

Gebrselassie spends most of his racing time hunting world records - I've said before what a pity this is and how great it would be to see him take on the likes of Lel, Wanjiru and Kebede, but he has been content, for the last five or so years, to race the clock in a couple of races a year. His first attempt for the last few years has come in Dubai, where huge incentives, both upfront and for winning and breaking records, are a big draw.

And Dubai has been very fast for Gebrselassie - he has run 2:04:53 and 2:05:29 (2nd and 8th fastest ever at the time, respectively). But 2010 has produced the slowest of his three Dubai Marathons, 2:06:09.

Dubai 2010 - close for a short time, then a gradual slide away

And the record was on for a short time only. The graph below shows the kilometer splits, and then I've worked out the projected time at 5km intervals (based on the cumulative time, not the last 5km, note), shown in green where he sped up over the interval, red where the pace slowed.

Remember that the world record of 2:03:59 requires an average kilometer pace of 2:56. Gebrselassie was close to it, but never below it, until 5km had been covered, and his 5km time of 14:54 was 3 seconds per kilometer off that required pace. We've discussed before how incredibly precise the pacing has to be in order to succeed over 42.2 km - it is remarkable. In previous Dubai races, Gebrselassie has gone out much too hard - in 2008, he was on course for about 2:02 after 15km, and then slowed considerably to run 2:04:53.

This time, if there was a pacing error, it was on the slower side of desired, because the early pace was just outside the target - Gebrselassie averaged 2:59 for the first 5km (14:54 split), 2:58 for the second 5km (10 km split of 29:42), but then began to slow progressively. At halfway (1:02:51), his projected time was 2:05:42, which some would say meant the record was still on, but when you need to run the second half of a 2:04 marathon in 61:07, then the record is pretty much gone. That the pace was slowing after 10km is a sign that it was never going to happen today, and from that point onwards, only eternal optimism would have kept record hopes alive.

A race in the final kilometers?

The pace held steady at around 2:58/km from halfway to 35km, and then the pace really did slow down - a series of 3:05 or slower kilometer times and the projected time dropped outside 2:06. It is very interesting to note that Gebrselassie's final kilometer was 2:36, an increase in pace which suggests that he took the foot off the gas in those earlier slow kilometers, because by then the record was clearly gone - it would have required something in the range of 2:50/km for the final 10km to challenge his mark.

Also of interest though, is that he "only" won by 24 seconds today, making this the closest marathon "race" he's run in a while. He may have entered looking for a paced record, but he seems to have found himself in a tight battle at the end.

And, given a final kilometer of 2:36, the 24 second winning margin would have been largely, if not entirely, created in the final kilometer, which means that Gebrselassie was not alone at 40km, and definitely not at 30km. It seems likely, then, that the presence of other runners in a group from 30km onwards, combined with Gebrselassie not feeling quite up to the world record (as shown by the relatively sluggish start, particularly from 10 to 20km), resulted in a tactical race which slowed the pace down in the latter kilometers.

I confess that I didn't see the race, it wasn't televised and SA internet is so poor that watching online doesn't happen at the best of times, so I don't know the circumstances in those middle kilometers. The temperatures and wind certainly don't seem to have been too limiting - the temperature at the finish of the race was 18 degrees with no wind, though the humidity was up at 80%, which may have contributed to that progressive decline.

Nevertheless, it's a good, not great time, for an athlete who has inspired expectations of great every time he runs. It really doesn't help that he only runs in time-trials (with the exception of Berlin last year, where Duncan Kibet might have, but didn't, provide some opposition), and that he talks up the chances every time he races. Before this one, he spoke of perfect preparation, and the ability to run 2:03:30. There's always the proviso that the conditions must be absolutely perfect, and so I suspect in the aftermath of this race, there'll be some problem with the conditions, perhaps that humidity.

We'll see, and update the post a little later, and maybe debate in the comments below!

Thursday, January 21, 2010

The complexities of gender verification: Legal, medical and performance dilemmas

I thought I'd interrupt the weight management series for a day to cover very briefly the news being reported out of Miami, where a panel of medical experts met to discuss the complexities around gender verification. The meeting, convened by the IOC in response to the huge controversy over Caster Semenya's win in the IAAF World Championships last year, addressed how authorities manage the minefield of equality of competition vs the rights of individuals and the medical concerns over such conditions.

It turns out, however, that fairness of competition didn't feature. That's according to one delegate, Joe Leigh Simpson. His words: “We did not address fairness. The entire concept was that these individuals should be allowed to compete.”

And the means to compete, according to news reports, is to treat the condition medically and not from the point of view of performance. That is, if they wish to compete as females, but have a condition which gives them masculine characteristics, they should seek a diagnosis and treatment. “Those who agree to be treated will be permitted to participate,” said Dr. Maria New, a panel participant and an expert on sexual development disorders. “Those who do not agree to be treated on a case-by-case basis will not be permitted.”

If this is the agreed upon approach, then fairness is very definitely an issue. One cannot be forced into medical treatment as a condition for participation, surely? The only reason to make medical treatment compulsory is to ensure fairness of competition, and so while delegates may say fairness was not an issue, it has to have been.

Other delegates have challenged this on the basis of fairness. The previously mentioned Dr Simpson admitted that the guidelines would be deemed unfair by some female athletes, but that “we have to balance fairness to female athletes to fairness to other competitors."

The question is, does the right to compete with a possible advantage as a result of masculinization trump the right to fair competition for those without it? Whose rights are more important, because balancing fairness requires that somebody assign a value to each side's arguments.

And legally, if an athlete decides not to seek medical treatment, can they be excluded from competing, unless some very clear guidelines are developed for how potential performance advantages can be evaluated. Can medical treatment be bartered against competing? As I see it, the only way this would be feasible is if athletic competition with such a sex ambiguity poses a risk - then authorities could say that they do not wish to be party to the increased risk and deny the athlete the right to participate. The risk of having such a condition alone would not entitle the IOC to ban an athlete, surely?

This discussion may in fact be happening as we speak, with Caster Semenya's lawyers and the IAAF locked in negotiations. Part of that discussion may involve terms for return to competition, and whether medical treatment is a pre-requisite.

As we've learned over the last few months, this is an incredibly difficult issue, with no obvious solution. Regardless of which way you swing, there are going to be winners and losers in the debate - someone is either excluded, or large numbers of athletes are possibly disadvantaged.

My personal opinion agrees with that of Doriane Coleman, a law professor at Duke University, and a former elite 800-meter runner. “If you start to do this you are making a joke of the fact that there are two classifications — male and female. They might as well open it up and have women competing with men.”

But that's because my paradigm is performance, advantage and fairness. Unfortunately, it's never quite that simple.

I'll get back to other "weighty" issues next week - feeling rather burned out at this stage, I must confess. Luckily the year is nearly over...

Wednesday, January 20, 2010

There are many reasons to want to burn fat during exercise. For obvious reasons, in the context of the series I'm currently doing, people want to burn fat during exercise to lose weight. In that regard, one must emphasize that as much as we talk about weight loss, fat burning (or rather, a change in body composition) is the priority for most people who commit to exercise and diet to lose weight.

I must emphasize (and this is a late addition to the post) that the principles we've been speaking about in our previous three posts in this series do not suddenly cease to exist - in other words, the fundamental issue is still total calorie balance, not necessarily fat burned. And so this post looks at fat use during exercise, but I don't want to overplay the concept that you can burn fat to accelerate fat loss. In fact, in the long term, it's the creation of the calorie deficit that is needed, as we discussed in Part 2 A and B of this series.If in doubt, read the whole series as one "book" and it should be clearer...

For those who are more interested in performance, fat burning is equally important. Ever since the 1970s, when the muscle biopsy technique first allowed scientists to "look inside" our muscles during exercise, we have understood that fatigue and performance are associated with a depletion in the body's glycogen stores. Delaying this depletion of your body's carbohydrate stores is seen as an important adaptation to training, and we know that highly trained endurance athletes have a much greater capacity to use fat. This is also the reason why science has looked at all kinds of strategies, like caffeine use, fat-loading, high fat diets and fat during exercise to try to delay carbohydrate depletion.

So, having made the case for fat burning, let's look at how it plays out.

A car with multiple fuel tanks: Fat vs carbs

You'll know that our body is capable of using numerous sources of energy during exercise - think of your body as a car with multiple fuel tanks. The first tank is glycogen, the storage form of carbs in the muscle and liver. The second is fat (strictly speaking, it is free fatty acids), which is stored in the muscle and in adipose tissue as triglyceride. This is summarized in the diagram below.

The problem we face is that our body's glycogen stores are finite - muscle and liver glycogen supply energy for exercise for about two hours (depending, of course, on the intensity, level of training and habitual diet, among other factors), and once they are depleted, hypoglycemia (from liver glycogen depletion) and fatigue are the result.

On the other hand, much to most people's dismay, fat stores are not limited. "Infinite" is not the correct word, because they're not, but in terms of physiology, you have more than enough fat to power exercise for much longer than you can ever exercise, even if you're an elite athlete. Most of us are not, and so our objective is to cut down these already abundant fat stores into something a little more "acceptable"!

For now, I won't go into the concept of "preferred fuels" and how the heart can use lactate, while the brain is able to use ketone bodies. I've also oversimplified by leaving protein out, but that's because I want to focus on fat vs carbs today.

Burning fat - how fast, how long?

Perhaps the best approach to this topic is to ask when each of the fuel stores is used? In otherwords, how does your body decide when to use fats versus carbs as a source of fuel, and to 'fuel' the discussion by starting with some of the theories around fat burning.

The first theory is that you burn more fat when you exercise at a low intensity. That is, walking is better than running, and cycling slowly is better than cycling fast, and so on. The idea is that your body uses carbs more and more as exercise intensity rises - this is the basis for target heart zones and the fat burning zone you see in books and on gym equipment.

Let's look at that in more detail. Below is a diagram that shows an example of how the use of fat and carbs are related as exercise intensity rises.

So, on the left, in the pink shaded box, you can see that at low intensities (walking, slow cycling), about 80% of your energy comes from fat, while only 20% comes from that carbohydrate (CHO) "tank". As the exercise intensity rises, the relative contribution of fat falls while CHO rises. The result is that at about 60%, shown by the green zone, the contribution is equal - 50% from fat, 50% from CHO. This point, at which the contribution from CHO becomes greater than that from fat, was called the Cross-over point by George Brooks, a very famous exercise physiologist, who wrote a great textbook on the field (the book that was prescribed to us in my studies, in fact).

Then, as exercise intensity rises even more, the contribution from fat declines, so that by the time you're exercising vigorously, between 80 and 90% of the energy comes from CHO, and only about 15% from fat.

Just to comment on how you can measure intensity, my value is calculated as a percentage of VO2max, which is not accessible to many people. It's impossible to say exactly what heart rate that corresponds to, because it is very much dependent on the person and the context of exercise. For some, it's a one-to-one relationship, so that 50% VO2max is 50% HRmax, whereas for others, heart rate will be higher than VO2max - 50% of VO2max would correspond to say 60% of heart rate max. I wouldn't get too hung up about this, for reasons explained below. I know it sounds simple, but if you're wondering what 60% corresponds to, it's 6 out of 10 on a scale of exertion, where 10 is maximum effort.

Note also that the cross-over point, and in fact the whole pattern of the two lines is quite 'malleable' in that training, diet and genetic differences affect the relative percentage. For example, a highly trained athlete burns fat more efficiently than an untrained person, and so they tend to use more fat at a given intensity. People who habitually eat high fat diets are also shifted to the right, meaning that they burn more fat at a given intensity. Sympathetic nervous system activity does the reverse, shifting the lines to the left, so that you burn more CHO and less fat at any intensity. So the point is, the above graph is an example, not an absolute guide.

Low intensity is better, right?

So, what you're probably thinking is that theory that low intensity exercise is better if you want to burn fat is correct. Well, think again. It is true that at low intensity, when you walk, most of your energy comes from fat, and that as you increase the intensity, less and less comes from fat.

But what is missing in this picture is the TOTAL amount of energy. Let me phrase it this way: Would you rather have 20% of the money in Jonathan's bank account, or 80% of the money in my bank account?

Your answer of course, should be that you don't know. And what you should be asking is "How much money is in your bank accounts?". The reason is, you'd be pretty annoyed if you took 80% of my money, because my bank account might be empty. Jonathan, on the other hand, might be loaded, and 20% of his money sees you retiring at 40! (Truth is, neither of us retiring early, which is why your donations are welcome! Kidding...)

So, look at the graph again. You should not be too pre-occupied with the percentage, but rather the total amount of fat that you are burning, because that 50% that comes from fat in the green zone might be more than the 20% that comes from fat in the pink zone. For answer to that, we look at a study done many years ago by Romijn.

Below is a graph that I've redrawn with some calculated figures, based on Romijn's study.

So, you're looking at the same kind of graph as before, showing how much of your energy comes from fat and CHO at different intensities (I've further divided it into muscle, liver and adipose sources, but that detail is not vital right now. Note, however that "Plasma FFA" refers to the fatty acids that originate from the adipose tissue - the triglyceride is broken down into free fatty acids which are used). This time though, there is also a measure of HOW MUCH total energy is being used, shown by the y-axis (in kCal/hour, for an 80kg man in this case)

So again, at low intensities (25% VO2max), you'll see again that most of the energy comes from fat (75% in this case), with only 25% from CHO. Jump to 60% and the fat contribution falls to 48% and then at 85%, fat provides only 20% of the total energy. This confirms what we saw in the first graph.

But, the key is that the TOTAL energy, shown here on the y-axis, rises as well, and so the 48% of energy from fat that you get at moderate intensity actually adds up to more TOTAL fat use than the 25% did at low intensity. Think of the y-axis (total energy) as the size of the bank account, if you will. The green boxes above each bar show the total amount of fat burned in an hour - 24g, 37g and 23g per hour at the three intensities.

The moral of the story, which is shown further in the graph below, is that if your objective is to maximize fat burning, low intensity is not necessarily the best option. Rather, moderate intensity burns more fat per hour, before a decline in fat use as the intensity rises beyond about 60%. The reasons for these shifts, incidentally, include increased sympathetic response to exercise, activation of different muscles as intensity increases, local regulation of metabolism in the muscle, and also the exponential nature of physiological responses to an increase in intensity. That's a post of its own!

Remember also that these are graphs based on calculations and measurements for a typical person - the actual values may vary for different people depending on training, diet and sympathetic activity, as mentioned. One also has to make some assumptions, such as VO2max values, the RER during exercise and how it changes with intensity. But I want to highlight the principle, not the values, so bear with those assumptions.

What does this all mean? The role of time and putting it into perspective with diet

So, what this means is that if your goal is maximum fat use, then lower intensities may mean a greater relative contribution, but it is moderate intensity that gives you greater fat use per unit time.

Time is key though, as many of you are no doubt thinking. If you do a low intensity session, walking (25% VO2max in the above graphs), then while your total fat use per hour is not as high as at say 60%, you might be able to do this exercise for three hours, compared to only one hour at a moderate intensity. Three hours with 24 g per hour (see figure) beats one hour with 37g. So duration plays an equally important role. What I am emphasizing is that for a given time, you will be better off at a moderate intensity somewhere between 50% and 65%.

The next point, before we get too carried away, is that the actual differences are pretty small. Not to discourage you too much, because exercise is vital for weight management and health, but one rule of thumb is that you can estimate total energy use during running by saying that you burn 1 kcal per kilometer per kilogram.

So, taking our 80kg man, who runs 8km (5 miles), he'll burn about 640 kcal. It doesn't matter how fast he runs, thid amount is the same (the difference, of course, will be how much time he spends burning it). Now, assume that half his energy comes from fat and half from carbohydrates. That means 320 kCal from fat, corresponding to 35 g (this is about the same as in the graph, since I based that graph on this kind of calculation).

So, 35 g of fat in 8 km or 5 miles. To burn 1 kg of fat, he therefore has to run 230 km (142 miles). Not very encouraging. There is an additional 'after exercise' effect, which one can't ignore, but I want to make the point that actually burning fat is not as simple as we often assume. In the words of Bengt Kayser, who pointed out this principle, it puts into perspective the resolution that says "I want to burn off 10kg of fat by running".

You can work out a similar thing for cycling. If you ride for an hour at 200W, your energy use is probably going to be about 800 kcal. If 50% of this comes from fat, then you've got 400kCal, or about 44g of fat. That is about the same rate of fat use as your 8km run gives you, and a lot of cycling to burn those 10kg of fat.

The value is in energy, not necessarily one fuel

And then perhaps most significantly, the key is still to create a calorie deficit, which means that you need not worry too much about whether your energy use is coming from fat or carbs - the key is to create that deficit, because in the long run, the energy will have to be provided and you will achieve similar results regardless. Again, I'm oversimplifying a little, because we have discussed how efficiency changes, and there are some issues as to how the nutrients are oxidized as they are ingested, but the principle is not necessarily to burn the most fat, but to create an energy deficit.

And this is where diet comes into the picture. If you want to create the energy deficit in order to lose weight, and notwithstanding that this is an oversimplification as we described in Part 2B of this series, then the combination of diet and exercise the way to do it, because to actually burn energy directly is a lot more difficult than people think. This is why the combination, and the long-term approach is so important. Things do not happen overnight in physiology, particularly when it comes to weight loss.

The progress can be slow, and invariably, when it is not, it's not sustainable. Crash dieting, starvation might lead to rapid results, but they also lead to subsequent rebounds, and health problems that we won't go into now.

But for the purposes of this post, which I'll wrap up because it's been rather heavy on numbers, the key point is that burning fat during exercise happens right across the range, and the ideal intensity, if you are looking to make the most of your time, is a moderate intensity, and not the low intensities that you'll often hear recommended.

Next time, we'll look a little more at energy use during exercise and the role of diet.

Sunday, January 17, 2010

No, not part 3 of the weight loss series, don't worry. Rather, it's a response to your many emails and comments to Part 2 of the series that looked at calories in, calories out, and the principle of weight loss. As usual, there are too many good comments to do justice to with an answer, so I'll thank you once again and move ahead to a general response. Also, I wanted to write briefly on what is still coming, because there are some things I want to cover in future posts which come up over and over in the early posts as well.

One common theme in your responses has been 'complexity', and this is something that has weighed (pardon the pun!) on me as I've written these last two posts. As I stressed yesterday, weight loss is not simple (obesity wouldn't be the fastest growing cause of death if it were), but at the same time, it must be simplified, because so many layers of misinformation have been added over the years (and the 87,000 books) that many have become entrenched as 'best practice' that it actually serves to go back before going forward!

The simplicity is the calories argument, the principle that energy out must exceed energy in for weight loss to occur. However, I wouldn't recommend taking the approach of counting calories to try to balance the equation, because of inaccuracy and unknowns on both sides of the 'scale'. I explained this a little yesterday, but there were two points that I didn't stress enough, and I have some of you to thank for raising them.

Energy sources

First, let's look hypothetically at someone whose energy intake is 3000 kCal per day, and who exercises regularly and is in weight balance. This person could, in theory, get that energy from 333 grams of fat. They could also get it from 750 g of starches. Neither is desirable, for both the obvious reason that a diet consiting entirely of only one food group would be sorely lacking in important nutrients and you'd end up less healthy than Morgan Spurlock (the guy from Supersize Me).

However, what is more vital is to recognize that you don't simply add up the numbers, because the macronutrients (carbs, fats and proteins) have a more complex role than simply adding calories to the body. Carbohydrates are the primary source of energy during exercise, and for the brain pretty much all the time. Fats play a role in cell function, and proteins are crucial for cell repair and for muscle recovery after exercise. You can have too little of each, particularly carbohydrates. Perhaps the biggest trend in fad diets in recent years is the shift away from carbohydrates, with the principle that fat can provide energy. That's true, but only up to a point, and an athlete without carbohydrates is a dangerous proposition - impaired performance and immune function are two of the consequences.

The point is that your objective with diet is not to simply tally up the calories, you also have to manage the diet for health reasons. There are many theories on how to achieve this - there's a 40-30-30 principle, which says that 40% of your energy should come from carbs, and 30% each from fats and proteins. Then there's the theory that those doing more exercise should aim for 60-30-10, then there are the "anti-carb" diets where only 10% of the energy comes from carbohydrates, with most from proteins. There is a great deal of debate around these diets, which balance is optimal. I'll try to get to that later in the series, or in a separate post in collaboration with a dietician (because if you want to offend people, tell them their diet is not optimal). I firmly believe, however, that anyone who is basing their weight loss on exercise, or who is training for performance, must ensure that their carbohydrate intake is sufficient, or they will be compromised.

Now, before this becomes a post of its own, let me address the second point.

Complexity in calories

Take the case of a person who has recently come down from 250 to 230 lbs, and is attempting to lose a further 20 lbs (± 10 kg), through the use of diet and exercise. But, much to their dismay, they lose nothing. Some will say that this person has matched their calories in and calories out but not lost weight, thus discrediting the principle.

The problem is, you can never know with certainty what has happened to energy output. Until you measure it exactly (which requires complex equipment and is highly impractical), you assume that calories out is accurate. It may not be - there is a lot of evidence that muscle becomes more efficient when weight is lost, which would impact on how the estimation for energy expenditure is made. Suddenly the energy intake is again greater than it should be.

Similarly, metabolic adaptations to conserve energy have been identified. For example, a reduction in body weight (specifically, fat) causes a fall in the levels of two hormones, leptin and thyroid hormone. Problem is, when these hormone levels fall, appetite rises and metabolic rate actually goes down. If you inject leptin, incidentally, you can prevent this drop in metabolic rate (Rosenbaum, 2002 & Rosenbaum, 2005). So, referring again to the figure from yesterday (shown again below, but with the modification after metabolic adjustments), your body actually reduces the resting energy expenditure in response to weight loss, which may create an energy surplus.

This is yet another reason why I don't advise the approach of counting calories to try to match the two sides - your body is too smart, and too complex for that in the longer term! Trying to pre-emptively calculate the body's response is fraught with error, because of inaccuracy of measurement, and complexity of physiology. Yesterday, I mentioned the example of an individual who remains weight stable over a 10 year period. What I was getting at, but didn't put across correctly, is that weight balance is incredibly complex - over 9 million calories balanced in a ten-year period. That doesn't happen by accident, and it doesn't happen by preemptive design. It happens by physiology! And so losing weight requires the same principle - don't micro-manage the scale, rather be sensible and allow the theory to work for you, not to work the theory!

Final word on appetite

Then finally, something I absolutely must cover (and hope to) is the "listen to your appetite" theory. Your body is remarkable and it does signal to us when we need to rest, to eat, to drink, and even what (a salt craving for example, is part of the exquisitely regulated osmolality homeostat that sports drink companies don't want to recognize!).

However, in the case of diet, we're subjected to too many external influences that affect appetite that many people cannot rely solely on how they feel in order to eat correctly. There's some great research on this - Brian Wansink has done some studies with interesting titles like "Is this a meal or snack? Situational cues that drive perceptions.", and "How visibility and convenience influence candy consumption." He has also written a book called Mindless Eating: Why We Eat More Than We Think, detailing this fascinating phenomenon. (just a note - at the end of the series, I'll do a book list with some recommended reading on weight loss, looking at both exercise and diet)

Then there is the psychological component of food, which cannot be ignored, because our desire to eat is not simply 'physiological' in that stress and emotional cues trigger eating (we all know this as "comfort food", among other things). I would argue that these are still physiological, mediated by neurotransmitters in the brain, but this is semantics. Point is, we may not be able to trust that our body signals when to stop or to cut back. And then finally, I've already mentioned that with reduced weight (and fat mass) comes a fall in leptin, which then increases our appetites, playing havoc with the theory as our weight changes.

All in all, a complex issue, and another one to tackle in detail later (if not in this series, then in another).

Looking ahead

So that's it for my "short" reply to your posts. I just wanted to consolidate yesterday's posts, but I guess there were a couple of key points to make. The principle of increasing energy expenditure and cutting down energy intake is without doubt the simple solution. Achieving this is difficult (but this does not make the principle wrong, take note), and there is a physiological layer of complexity that makes it impossible to preemptively manage energy in and energy out. What it boils down to is systematic sensible choice, with expert support to get the principles correct.

Part 3 on fat is on the way - probably later in the week, I have a presentation to work on first, so forgive the sudden "loss in momentum" of the series.

Saturday, January 16, 2010

Thanks to everyone for your comments and emails in response to part 1 of our series on Weight loss and exercise. It's always great to debate the issues, and in this particular case, I value your thoughts even more because it will help steer the remainder of this series in a direction that I hope meets most expectations.

I realized overnight what an enormous challenge this topic presents - there is simply too much content and too many angles to cover, and so I have no doubt that I will fail to do justice to some of the sub-plots in this fascinating area. However, as I stressed yesterday, my approach here is to look at weight loss from a general point of view, not an elite one, because weight loss transcends performance boundaries. Of course, it will feature, and I know many of you work in that performance realm - we're all about high performance here, so it will come up, but I hope to tap into a different area of exercise physiology in this series.

Perhaps one day, I can team up with a dietician and some researchers in this field and produce the book that covers ALL the angles! Thinking back to yesterday's post, where I mentioned that there are already 84,000 books on weight loss, I think a good title for a book would be "The devolution of weight loss. Back to basics", because it occurred to me that the evolution of the obesity pandemic has co-incided with the explosion in "knowledge", when all along, the answers are pretty basic. Tough to implement, make no mistake, but basic in theory.

And that, the basic approach, is what I will try to unpack in this series, starting today with the basics of energy balance.

I have no doubt that all of you know the basic premise behind the "scale" of weight loss, which says that your body mass is a function of the balance between the energy intake and the energy output on a daily, weekly, monthly or yearly basis.

On the left hand side of the scale, you have energy intake, in the form of food. Each has a caloric 'implication' - 1 g of carbohydrate and protein adds 4 kCal, whereas 1 gram of fat contains 9 kCal (alcohol, incidentally, is 7 kCal/g).

On the right is energy output, and that is made up of resting energy expenditure (a combination of sleeping and awake), the thermic effect of food, because when we eat we actually increase energy use for a short period and different foods produce a different response. And then finally, there is the energy expenditure from activity, which is where exercise fits in, and which is the most "malleable" of the different components - it can be zero, or it can be enormous, if you exercise like a Tour de France cyclist and burn 5000 kCal per day in training or racing! This is shown in the diagram below.

The basic premise of weight loss is this: weight loss requires that your energy output exceed your energy intake for a prolonged period. Much like financial management, weight management is simply a balance between spending and saving - if you wish to save money, spend less than you earn. If you want to lose weight, eat less than you burn (eat your heart out, Shakespeare. Thanks Bruce!)

In any event, this principle is behind pretty much every strategy ever devised to lose weight. Hours of exercise to add to the right hand side of the scale, or starvation diets or any one of the millions of other diets to reduce the left. Or weight training to try to increase resting metabolic rate, and even eating specific foods like chillies to try to increase the thermic effect of food. Some of these are more effective than others, as you can imagine, and it's the intelligent reduction in energy intake combined with the increase in energy expenditure that will ultimately lead to weight loss (and note that the operative word is "intelligent").

So, in Time magazine's controversial article, exercise took a knock because of what was called the compensation effect. An hour of exercise could burn anything between 300 and 1500 kCal, depending what you do - run like a Kenyan and you'll be up at 1500 kCal, walk slowly and you're at the bottom end (this huge range illustrates one of the biggest problems with this calorie "counting" approach, as we'll see shortly). The problem is that if you do this time, but don't also manage your diet, then it's possible to replace all that energy, and then some, with just one meal or snack. The end result is that the scale tilts in the WRONG direction and you gain weight, not because of exercise, but because of the dietary choices you make in association with exercise!

For example, compare the following two ways to spend a Sunday afternoon:

So, on the left, the exercise option can be all but canceled out by diet, in this case a can of Coke. In that regard, you'd be better off watching television for 30 minutes and eating nothing. This was basically the take home message in Time's article, which clearly misses a big part of the picture. If you make the same dietary choices by drinking a Coke in Option B where you remain inactive, then you shift in the other direction, and may gain weight. All things being equal with regards to diet, exercise is valuable - how many people exercise as a reason to indulge in foods that they otherwise would not be able to?

Let me emphasize, however, that there are many other reasons why Option A is the better one - for one, you can't simply not eat in order to lose weight, and so Option B is not really feasible in the long term. Second, life is not a game to see if you can balance your calories - there's more to it than that! Third, the health benefits from exercise are not captured in a single number of calories out minus calories in. These are all crucial aspects and I want to stress that one should not get too hung up on the minutiae, but rather understand the principle.

When details matter

All of this is obvious, and forgive me for oversimplifying the situation, but you'd be surprised at how easy it is to be tripped up by this simple principle. If you are embarking on a weight loss plan, and have yet to see significant results despite diligently exercising for 45 minutes a day, then the answer is likely that you still haven't addressed the other side of the scale adequately. If you have reached a plateau in weight loss, then the same may be true - it's time to consider how much you eat, when you eat it, and what you are eating, because you may unwittingly be negating your exercise with simple dietary practices. And I must stress this - what you read in books and see on TV is generic advice - it can only take you so far. There will come a point where you need specific advice and that is where consulting a dietician becomes vital, especially for the more complex situations.

Take for example a more serious athlete, who is looking to lose the final 2 or 3 kg to get down to racing shape. They may train for 2 hours a day, and burn in excess of 2000 kCal during those two hours. However, even a "healthy meal option" can put that back in one sitting. Here in SA, we have a chain of health shops called Kauai, and most serious athletes would not think twice about eating there (think organic food, smoothies, rye breads and everything you read is healthy - I'm sure you have these stores in your country).

Problem is, a typical meal at one of these stores, consisting of a breakfast wrap and a low fat protein smoothie, adds back 1600 kCal. The end result is that 2 hours of exercise goes nowhere, and our cyclist, despite training as hard as his body can tolerate, does not lose that weight. The only solution here is to manage the details - portion sizes, content and even the timing of the meal.

For example, there is evidence that if you delay eating after exercise for about an hour, you burn more fat than if you eat right away. This has to do with keeping insulin levels down, and insulin is a hormone that drives carbohydrate use, while "tuning down" fat use. The problem is, if you delay eating, you may compromise your recovery, which means you can't sustain high quality training day after day. You also can't cut carbohydrates out, and you certainly can't under eat - there is compelling evidence that the biggest risk factor for becoming sick during intensive training is an energy deficit.

You may also have read that if you train before eating, you rely more on fat and this would lead to greater weight loss. In theory, yes (it has to do with availability and insulin again), but practically, you might battle, because the risk of hypoglycemia is higher, you may not recover well from the metabolic stress, and because the body is often too smart to be tricked in the long term. You therefore have a dilemma if you are trying to train hard and struggling with stubborn weight. Each case would have to be managed on a case by case basis, and I can't stress enough that seeking out expertise to discuss these details is essential - generic advice only takes one so far, after which time books, websites and magazines can't help any longer. Dieticians fulfill this role, although I will touch briefly on these issues in future posts, so don't worry, I'm not leaving you hanging completely!

Calorie counting - guaranteed weight loss or futile exercise?

Returning to the energy balance scale, everything I have written so far is probably steering you into thinking that if you simply measure what you eat, and measure how much you exercise, you can balance your own scale and lose weight.

And you'd be swimming into dangerous waters by doing this. Let's look again at the scale - there are two sides that you would have to manage, Energy Intake and Energy Output.

On the Energy Intake side, you have the following problems:

You would have to cook all your own food and measure everything that goes into it, which means you can't eat out and you limit your options to only what you can measure

Not all foods have clear labels, so you would invariably miss certain measurements

On the energy output, the problems are even more numerous:

You can't know with certainty how much energy you have burned during exercise - there are reasonably accurate estimations, based on heart rate and many studies, but precision is beyond us

You cannot quantify the other aspects of this side of the scale (see the diagram above), particularly the resting energy expenditure and the thermic effect of feeding, which make up an enormous part of the total. Get this wrong by even 5% and you're looking at a big error in your calculation.

There is a substantial increase in energy use AFTER exercise - this post-exercise elevation in metabolic rate is not accounted for by tables. So you might run for 60 minutes and burn 800 kCal, but the actual total thanks to exercise is higher. Quantifying this is a problem.

Now, the point is that you cannot measure these things accurately, and therefore you cannot micro-manage this. Here's an illustration of the complexity: An 80kg man who remains at the same weight for 10 years has, over this period, managed to balance a grand total of about 9.1 million kCal. In contrast, if he gains 10 kg over this period, it's because of a mismatch of about 70,000 kCal. In ten years, that works out at 19 kCal per day.

In other words, you can try to measure your calories in and calories out, but if you're systematically inaccurate by 20 kCal per day (the equivalent of a sip of Coke), you gain 10kg. My point here is that counting calories, unless it's done with absolute precision, is not a good method to manage your weight.

Where calorie counting is helpful is in creating awareness about diet, and if there's one thing you remember from this series, it is that awareness is perhaps the most powerful ally you have in trying to lose weight. There are studies, for example, that have found that having people write down what they eat every day (volumes, sizes and content) leads to significant weight loss, even though they are not told to do anything else differently. Similarly, if you are on an exercise programme, and you write down what you do and what you eat, you lose more weight than if you exercise 'blindly'. In both instances, it is awareness that helps, because it guides sensible food choices, smart exercise and it is this combination that helps to produce sustainable weight loss.

So knowing what you put into your body, and knowing how much you burn, can help guide you. It may be the catalyst behind making sensible choices to reduce portion sizes, or change the content of your meals slightly, or maybe increasing the time you spend exercising. If you have an idea that your daily energy intake is 2500 kCal (give or take, because as I've said, absolute precision is out of reach), and you're exercising for 30 minutes at a moderate intensity (± 400 kCal, added to a typical day of about 2000 kCal), then you can correctly deduce that you need to change something - either train for 40 minutes, or train slightly harder, or cut down on portion sizes, and you'll start to see results.

Next up - fat burning 101

Forgive me for what may seem a very basic approach - I did say that a book on this topic should be called "Back to basics", because so much complexity has been added to this by all kinds of gimmicks and 'revolutionary' ideas that hopefully it's a refreshing reminder that the actual principle behind weight loss (and the reason we often fail) is pretty straightforward.

I don't mean to trivialize the problem, though. If it were simple, fewer people would struggle. But the principle is straight-forward - implementing it, sticking with it, not quite as easy!

What we need to do next is discuss exercise and energy use, particularly around fat burning. What intensity? How long? Do you only start burning fat after an hour? How do you manipulate it?

That's coming up in Part 3. Sorry for the long post - I wanted to split it into two, but it wouldn't have made sense. And just so you know, you've probably burned 20 kCal while reading this! But don't worry about the number!

Friday, January 15, 2010

I've long felt that one of the biggest privileges of being in the field of exercise science is that what we (sports scientists, that is) study is relevant to just about everyone. If botanists have flowers and gardens, if astronomers have planets and stars, then sports scientists have...performance, and weight loss.

For almost three years on this site, we've focused almost exclusively on performance aspects - elite athletes, pacing, doping, world records, technology, and have had little emphasis on weight loss. But the reality is that if ever there was an area of exercise science that was relevant to everyone, it is weight loss. Whether you are into optimal performance, where carrying 1kg of excess weight is the difference between winning and losing, or whether you are an individual who is told to lose 50 kg (110 lbs) to stay alive, weight loss features on everybody's horizon.

And so we turn our attention to the issue of weight loss and exercise, with our new series, which we hope provides food for thought, and maybe inspiration, regardless of which category you fall into!

The global pandemic and meeting the needs of the market

You've all heard the statistics, I am sure - that obesity is the fastest growing cause of death in America. That two out of every three people in the USA is overweight or obese, and that this figure is rising, both in the US and the rest of the world. However, statistics like these are often far removed from what would drive you to take up the weight loss challenge for yourself. It's all good and well knowing that two in three colleagues may die from a preventable disease caused by obesity (and that you may be one of them), but the real driver for most people to lose weight is closer to home. So as you read this, your primary concern may be the 5, 10, or 50 lbs that you are looking to lose. And it's that angle that I wish to take in this series, without dismissing that there is a global problem that needs to be addressed.

Now, when it comes to weight loss, there is no lack of a demand - it is created by your desire to perform, to look better or to be healthier. This market is enormous, a multi-billion dollar industry, and it borrows from science to pitch a dizzying array of exercise machines, programmes and diet plans at consumers, who, desperate for an answer (in a short space of time) will jump at anything that promises to meet their need. For example, if you do a search on Amazon.com for "weight loss" and you will discover 83,798 books, which is up from 67,000 books back in May last year. That means that 17,000 books have been added in under a year. You will also find two TV games, 7 shoes, 6 items of jewellry and 180 music items which have some association with weight loss.

One of these books is "The Cardio Free Diet", written by a Chicago-based personal trainer, named Jim Karas. The book cover promises results in only 2 weeks (this is a classic tactic to hook consumers with), and it proclaims "real results in only 60 minutes a week", "lose the cardio, lose the weight", and "Kiss the treadmill goodbye". The first line of the book, incidentally, is "Cardio kills. Your joints, your time, your motivation, and your weight loss goals".

We may get into the details later in the series, but for now, suffice it to say that none of this is true. Where a tiny element of truth exists, it has been twisted beyond all recognition, or buried beneath sensational advice in the interest of the angle. This book was a bestseller. Why? Because it recognized the need, and then it pitched to consumer an idea that was almost irresistible - that they could lose weight in next to no time, with no cardio at all. Consumers buy this book because they desperately want it to be true, and are willing to try anything to lose the weight they believe they must.

Unfortunately, this book, and many like it, covering topics like diet, exercise, equipment and medicine, represent "cutting edge knowledge" that has witnessed the greatest explosion in obesity we have ever seen. Something is wrong with this picture...

Enter Time magazine and the "myth about exercise"

Into this environment, you introduce Time magazine in August, 2009. A cover story, shown left, promised to reveal the "Myth about exercise", saying that it won't make you lose weight. Inside, the article produced quotes from professors who said that "In general, for weight loss, exercise is pretty useless". It told us that vigorous exercise would lead to weight gain, and it explained how years of advice to exercise to help with weight loss was only making us fatter.

It was, not surprisingly, met with a fair degree of condemnation within the exercise community. I have no doubt, however, that it also attracted a fair amount of attention, and maybe led to the sale of a few Time Magazines that may otherwise not have been sold - remember, the market is saturated with advice and information on a very topical issue like weight loss. Standing out in the crowd requires a hook, and telling thousands of people who have exercised for years that they are wasting their time is a pretty strong hook.

I bring this up only to make the point that the content of the article, and the angle which is uses to approach the subject must be understood in order to interpret what it said.

The compensation effect - a valuable insight on weight loss and exercise

The truth of the matter is that the article raised some very interesting points. The central theme is what was called "the compensation effect", the phenomenon where people who exercise without concern for how they manage their diet MAY (not WILL, as the article suggests) actually overshoot their requirement and begin to overeat. The result may be weight gain, or failure to lose weight.

The article cites one or two studies, in adults and in children, where this has happened - exercise fails to induce weight loss, and one theory is that our subconscious energy intakes simply rise to match expenditure. The article also includes a few quotes from highly respected scientists. Take for example the following quote from Prof Timoth Church of the Pennington Biomedical Research Center, who is the author of one of the quoted studies:

"I see this anecdotally amongst, like, my wife's friends," he says. "They're like, 'Ah, I'm running an hour a day, and I'm not losing any weight.'" He asks them, "What are you doing after you run?" It turns out one group of friends was stopping at Starbucks for muffins afterward. Says Church: "I don't think most people would appreciate that, wow, you only burned 200 or 300 calories, which you're going to neutralize with just half that muffin."

There is nothing incorrect with this at all - it's true. It's common sense. But common sense doesn't sell very well, and it certainly doesn't stimulate huge debate, which is why the context of these quotes was changed in the article.

But the point I am making is that the article is not nonsensical and completely false. It actually contains some vital information, which may have been overlooked in the heat of the debate. The bias of the article is shown in the fact that the author, on numerous occasions, writes that "exercise won't make you thin". One word would have changed everything, because had he written "exercise might notmake you thin", the statement would have been accurate!

Weight maintenance and health - what was left out

The other major criticism of the article is what it left out, rather than what it included. This is often the case of course - it's what you DON'T say that causes the problems! And in this particular article, there was no mention at all of numerous studies that have found that exercise is beneficial for weight loss, and crucially, weight maintenance, as well as health of physically active people. A vast body of research exists to show how exercise improves weight maintenance, working hand in hand with diet and other lifestyle choices to help people get to, and then stay at, an optimal body weight.

Then there is plenty of evidence that shows how physical activity improves health - blood pressure, lung and heart function, cholesterol (lipid) profiles, insulin sensitivity, muscle and bone strength, and so forth. These studies even challenge the notion that weight loss should be a focal point for people who are exercising. They suggest that it is better to be fit, even if you are overweight, than it is to be within normal weight and unfit or inactive. However, this did not feature at all in the article.

Where to next? Unpacking the theory

So, having pointed out what was missing in the article, and how facts may have been embellished for the sake of sensation, we need to actually unpack the compensation effect.

So that will be the next part of the series - the theory of weight loss. This includes the infamous "calories in vs calories out" equation, the so-called energy balance, and the source of so much frustration and over-analysis. But the principle is vital, and that's something to look at, especially to consider how exercise and diet interact to change this energy balance.

Then, we'll look also at the benefits of exercise - the health impact of regular physical activity, which was so completely overlooked by the Time magazine article. For now, this was an introduction, a quick glance back at the Time piece, which sets the scene for the series to come.

Thursday, January 14, 2010

Caster Semenya to run next month? Some thoughts on what is really going on

I know I said that I'd be tackling weight loss and exercise, but we always try to cover breaking news on science-related topics, and so I felt compelled to shift that series back by one day (don't worry, it's on the way!) to comment very briefly on the latest in the murky world of Athletics South Africa and Caster Semenya, since it is big news here today.

It is today being reported that Caster Semenya WILL race in the local season, starting in a few weeks, here in South Africa. Her coach has further stated that she will compete internationally, and he is preparing her to race in the Commonwealth Games at the end of the year. His position is backed by statements from ASA which yesterday supported that Semenya was clear and eligible to compete.

Unfortunately, as has been the case on numerous occasions in this ongoing saga, another day brought with it denials and confusion. First, the IAAF and Semenya's own lawyers denied that any decision clearing her had been reached. To them, the matter is still under discussion and they will only comment once the decision is made. Then ASA acted by distancing themselves from the issue, saying that it is a matter for Semenya and her family, and that they have not received any clearance from the IAAF.

Not suspended, and therefore eligible to compete

Legally, of course, the IAAF have not banned her. No suspension was ever handed down, and so in theory, she can run, as ASA recognized at the recent launch of the local track season. However, there is more to this than a simple legal issue, and were she to race locally, it would once again stir the hornet's next of allegation and counter-allegation that erupted last year in August. Unfortunately, people have not seemed to recognize that a failure of a ban is not necessarily an endorsement of her eligibility to compete. Meanwhile, her coach has clearly decided that he will plan the season without factoring this in, and perhaps this is all he can do - the alternative is to sit around waiting for a verdict, by which time 2010 may be beyond salvation as a competitive season.

So Semenya can go ahead and run, because legally, there's no barrier. Whether this is the best for her does not seem to factor in the decisions of those in charge. Remember, prior to Berlin, the medical advice was that she should not run pending further testing, and this was specifically to protect her against the potential fallout. That advice was ignored. Now, five months later, a similar situation exists - there is no concrete reason why she should not compete. But given the doubt, the enormous question mark over her, does it really make sense to put her back into competition? Is it really in her best interests to run until the verdict arrives, or is the prudent, wise approach not to wait on that decision and then run without any questions at all? (assuming this is possible)

Only a few possibilities

The latest round of statements and counter-statements does suggest some interesting possibilities, however. As I see it, the latest reports strongly suggest that Semenya IS intending to run again - her coach may be wrong about her being clear to compete right away, but he certainly wouldn't speak so openly of her plans if she did not have the intention of running again. To plan a season, and then communicate it means that the option of early retirement is not on the table, for now.

This then has a couple of interesting implications. Because she has decided to attempt to run again, there are only two possibilities:

a. She has (or is in the process of), with the help of her lawyers, managed to cast enough doubt over the possibility that she has a performance advantage that the IAAF have to allow her to compete without any requirement for surgery or medical treatment. She will have effectively done the same as Oscar Pistorius, but behind closed doors, and that is to force the IAAF to prove that her condition (assuming it exists) gives her a performance advantage. Failing to do that would mean that the IAAF would have to allow her to compete. If this scenario is the case, then all that is still needed is an announcement, but I cannot see the reason for the delay.

The second possibility - medical treatment to clear her to run

b. She has gone ahead with the surgery to remove the alleged internal testes, and now the way is clear for her to compete. The question is "when"? And this may be the debate currently holding up the announcement. We know from IAAF policy that a male can undergo sex re-assignment surgery, becoming female, and then be eligible to compete as a female after TWO YEARS of hormone replacement therapy.

The same standard, applied to Semenya, means that IF she has gone with the medical option and removed the testes, then hormone replacement therapy (with primarily estrogen), combined with a mandatory period of non-competition, would allow her to return to action without any questions over her eligibility.

Now, the question is, does she sit out for 2 years, or is that period shorter because she is not a 'male-to-female' re-assignment? Unquestionably, she was able to derive some physiological effects of testosterone, but not all, which would suggest the period should be shorter than 2 years. Is this the reason for the delay in an announcement? There are all kinds of physiological effects of reducing the testosterone levels - changes in muscle mass, body fat distribution, strength and recovery ability, but those are speculative at this stage, best left until the topic is directly in the news.

For now, all I am left with is the thought that either she is proving that she has no advantage from whatever condition existed, or she has gone ahead and cleared the way to compete according to IAAF policy by having medical treatment. All that remains in this second scenario (which I find more likely) is to agree upon the time to return to competition. And of course, if this is the case, then the statements made by coaches and officials that she will run locally suddenly become even more irresponsible, because the IAAF may very well return with a decision that says that she can run from the 1st of August, or some other date in the future. For now, those in positions of influence would do well to hold out and make sure they're not responsible for producing Episode 2.0 of the same drama we saw last year.

Wednesday, January 13, 2010

Tomorrow I will begin the first major series of 2010 - Exercise and Weight loss, which is mainly in response to Time Magazine's article last year, which explained "Why Exercise won't make you thin".

Exercise and weight loss is a topic that we absolutely had to cover, because for all the focus we've had on high performance, elite athletes and science in sport, the aspect of exercise, weight loss and the science behind it is probably bigger. I would be very surprised if anyone who has ever trained has not done so with a view to losing weight at some stage. Whether they're elite athletes who need to lose weight to get down to optimal racing weight for performance, or whether they are exercising on doctor's 'orders' to lose weight to become healthy, weight loss is a concern for everyone, and so it's a huge topic, and I'm sure this series will not be the only one we ever do on this subject..

So Time magazine helped inspire the series that I'll begin tomorrow, but I don't want to limit myself to that only. So we'll look at some practical applications, some of the science of weight loss, and we'll get some expert opinion that will hopefully help you, regardless of your motive! That's to look forward to tomorrow!

Doping - the illusion of steroids

For today, just as a 'filler' post, I want to link to two articles that really provide a great deal of food for thought on doping.

The first, written by David Epstein of Sports Illustrated, features an interview with an expert on doping in the USA, Professor Charles Yesalis. The interview was in response to Mark McGwire (he of steroid induced home-run hitting in baseball) saying that in his new position as hitting coach for the Cardinals, he would tell young players that steroids "are an illusion" if they wanted to know the impact of the drugs on their play.

The article is short, featuring a few questions to Prof Yesalis, in which he spells out his criticism of that position. It is a position that says that the denial of the effectiveness of drugs undermines the credibility of the scientific and medical fields, and I agree. We've seen this a great deal in cycling too, where people are saying that the doping practices in the sport don't have a significant impact on performance. It's part condoning the practice of doping, part denial that the problem exists, but the end result is that those opposed to doping lose credibility with the athletes. If you have more time, you may also be interested in this article, also by Epstein, from 2008, looking at steroids in much more detail.

This is a commonly asked question - "if they are doping, then how do they get away with it?" and the link provides some of the answers. Remember also the much more basic method used by Dwain Chambers, where he would fill up his mobile phone's message service so that testers who called him could not leave a message, and then when he knew he would test negative, he deleted those messages and allowed the testers to contact him. That was the "duck and dive" method (his words), a little less sophisticated than what Papp describes in his article, but apparently quite effective - Chambers was only caught thanks to the THG tip-off, and had been using everything for a long time without detection.

There are other methods too. Micro-dosing, urine substitution, enzyme treatments - all described briefly in the article. Scroll down to the comments section to read more interesting discussion. There is this one, which I'll paste here:

Prentice Steffen, ex-doctor at US Postal said the following to L'Equipe in an interview on October 6, 2005. I quote Steffen :

"Before going to the start of the Tour, the riders of certain teams, during their training camps, took EPO (which disappears from the urine within three days, even 12 hours when small doses are used) and took their hematocrits up to around 60. Then a doctor withdraws their blood, saving it in special containers, to lower their blood parameters into the accepted range (50) so that they pass without difficulty the medical controls before the Tour. Then, as the teams well know, during the race the vampires (2) can arrive any day but always between 7 and 8 in the morning. After that time, there is no more testing and the riders were able to re-inject their own blood. They were racing the stage with an enormous advantage- their hematrocrit in the 55 to 58 range during the race- then in the evening at the hotel, someone again withdraws their blood so that they sleep without risk (3) and, especially, they escape the possible tests the next morning.

L'EQUIPE:

This practice was used every evening during the three weeks of the Tour?

STEFFEN:

No, just for important stages in the mountains or maybe for a time trial. It's so simple to do and there's no risk of being caught unless the police intervene. The blood was shuttled by motorcycle in a refrigerated compartment... "

Transparency and urgency

Whether this should be described in public is debatable. I think the more transparent things are the better. Cycling's biggest failure, in my opinion, has been its concerted effort at burying the problem, either pretending it doesn't exist or downplaying its impact, as we said above.

The only way the problem of doping will ever be controlled is to expose everything, the good and the bad. Everyone should be invited to contribute to this 'cleansing' - I believe that a big part of the reason that cycling today is becoming cleaner (which I believe - see our interview with Yorck Schumacher for his views) is because the media and sponsors drew a line and started to attack doping. When the media decided that they would cover only doping and not the racing action, cycling had to respond.

Being transparent is the solution, and I find it positive when people talk, breaking the code of silence that exists in the sport. Unfortunately, not everyone agrees, and its for this reason that pro-cycling is where it is. A cyclist who exposes even a tiny part of the truth can expect to be bullied into retreat within the peloton, their credibility and integrity attacked with alarming aggression, ala Simeone and Bassons (and others, I am sure).

Let's hope everyone is listening. I'm sure they are, and I have no doubt that the net will close on all these methods as much as it can.

Join us tomorrow for the start of the the Weight loss investigated series. And thank you to Norman and Ron for providing links to those stories!

Saturday, January 09, 2010

We trust the second decade of this century has begun well for all of you, and that your new year's resolutions are still in tact! So far, it has been a relatively quiet year in sport - there has already been a 2:08 marathon (Feyisa Lilesa of Kenya in China), and a few sports events have taken place around the world. It seems as good a time as any to bring out the Science of Sport crystal ball, and also lay out what we'll be looking at covering on the site this year!

Tennis - an open season for the men, and a boost in interest for the women

Things hot up over the next few weeks - the Australian Open in Melbourne always produces great drama, and with Nadal, Federer, Djokovic, Murray, Del Potro and now Davydenko and Soderling all realistic title contenders, the men's tournament promises to be as hot as the weather conditions that often plagues the Aussie tournament!

Even the women's tournament holds some intrigue this year - I say "even" because in the last two or three years, women's tennis really has lost much of the excitement that comes from having big-name players challenging one another regularly with unpredictable outcomes. The return of Kim Clijsters and now Justine Henin changes that, because you finally know that there are two, perhaps three women (if Maria Sharapova can stay injury-free) who can consistently produce world-class performances and challenge the Williams sisters over the course of a season. It is a much needed boost for the women's game.

Some science of tennis is on the cards for the tournament, particularly if it is a hot one - there is some great research on pacing strategies in tennis, looking at how the temperature affects the game, and we'll bring you that discussion during the course of the tournament.

Given how the men's game now has eight men who could beat one another on any day, 2010 will be the most open year since Federer began winning Grand Slam titles in 2003. Federer was a name on just about everyone's list of the top 5 sports people of the 2000s, and deservedly so. However, I have to wonder whether we didn't see dominance in the absence of any real competition during the period from about 2003 to 2006, when Rafael Nadal (aged only 20 back then) turned his attention to hard and grass-courts to go with his clay-court dominance. Remember, the man who Federer most often kept from winning Grand Slam titles in that 3 year stretch was Andy Roddick, and with respect, he's not a name that many would put on a list of great champions. Was Federer great or was the game at the time in a lull outside of his high standard? The eternal debate, I guess.

So Federer's monopoly over tennis in the first half of the 2000s was gradually challenged, though his consistency - 22 consecutive semi-finals and at least one Grand Slam win each year since 2003 - has been perhaps his greatest achievement. Look for the former streak to end in 2010 - at some point this year, Federer will fail to reach a Grand Slam semi-final. The competition is now too deep, and the gap, once large, is now no longer existent. In particular, Rafael Nadal will look to 2010 as a year of redemption, especially on the clay, where his 2009 fell away. Reports from Qatar are that Nadal has worked on flatter, more aggressive ground-strokes to go with his heavy topspin, and if he can successfully implement that more aggressive game, he'll be nearly impossible to beat. It should be a great year. I pick Nadal to win 2 grand slams, Djokovic one (the US Open) and the fourth - at Wimbledon, anyone's guess.

Athletics - marathons, Diamond Leagues and world records

Athletics, and road-running, are our staple diet here at the Science of Sport, and so 2010 will feature a great deal of coverage, as always. The big 5 marathons will be the focus, as always. Starting with the Boston Marathon on April 18th, the marathon season should produce some amazing racing. Again, the men's competition looks deeper and stronger than ever, with last year's record of 103 sub-2:10 performances likely to be challenged again.

Wanjiru, Kebede, Gebrselassie, Kibet, and I dare say, two or three names we've not heard of yet, are likely to produce the year's fireworks. The first shot at a fast time comes in a few weeks in Dubai, where Gebrselassie always begins his year with the Dubai Marathon, his time-trial. He has pushed for the world record in each of the last two years, and this year should be no different, but whether his aging body (he seems ageless, but surely at some point it must begin!) can produce another sub-2:04, even a 2:05 remains to be seen. I feel he'll fall short, and then in Berlin, where it seems (for now) that the race against Wanjiru may well happen, we'll see his swansong in the marathon.

Then Boston features the American hopefuls Meb Keflezighi and Ryan Hall against the African contingent - the field is not confirmed just yet, but we'll cover it in detail as the race approaches. London is the week after, and that's where the fireworks really fly. Wanjiru, Kebede, and Martin Lel should all be there, looking for a fast time in what is always a race to boot.

Another name spoken of for that race is Zersenay Tadese. He got burned by the distance in his 2009 debut, but 2010 provides a second chance and surely, with his 10km and half-marathon credentials, he cannot fail at the marathon again. He may be the next big name over the distance. It would be difficult to bet against Wanjiru in London, given how he has fared in his last three marathons. But if Lel is healthy, that will be the race of the year. Lel is also aging, and 2010 may be his last big year. I'll pick Lel to win London, but Wanjiru to storm back and win in Berlin. New York and Chicago - we'll look at those later in the year! And the world record will survive the year - mid-2:04 will top the world lists.

The athletics season, meanwhile, sees the introduction of the IAAF Diamond League, which replaces the Golden League in 2010. More high-profile meetings is not a bad thing, provided it ensures head-to-head matchups and races, which is what the sport requires to continue its growth. Usain Bolt has put athletics right back on the map of public interest with his astonishing performances, but it's the races that the sport needs to sustain the interest - after all, world records cannot continue to fall every race. Hopefully, the addition of more meetings doesn't spread the talent too thinly and prevent those races. You can see the calendar of meetings here - the action kicks off in mid-May, and peaks in July, when the meetings come two a week.

The athletics season this year is "unencumbered" by any major international meetings, with the exception of the Commonwealth Games (more on this below). The big global games this year are the Winter Olympics, in Vancouver, in February, but for the track and field athletes, the absence of a global games means more flexibility in the training and competitive season - no qualification championships, no periods off, no heats and finals, just racing. That usually means more aggressive approaches to record attempts, particularly in the distance events, so that should be interesting to see.

However, I feel that the cupboard is pretty bare in the distance events, with Kenenisa Bekele so dominant, but I don't think up to the challenge of running 26:15 and 12:35 for 10,000 and 5,000m respectively. He has stated that his intention is to break the 3,000m and 5,000m records, so perhaps he'll come to the season prepared for it, but I just feel they'll be out of reach. Those records are now more than 5 years old, and getting back down to 12:35 range after spending 4 years running in the 12:50s is a mighty difficult challenge. So I think 2010 may well fail to produce a world record. Maybe the exception will be the 3,000m steeplechase.

In the sprints, it's all about whether Usain Bolt can continue to shine. There's no reason why he won't, but to continue breaking world records in a year where there is no major final may be asking a little too much. He'll probably scare the 200m record on more than one occasion, and should produce the most exciting moments of the year, but I would be surprised if we see more than one world record, at most, from the world's most famous athlete. What will be fascinating will be the match-ups with Tyson Gay, assuming we get them. Gay ran 9.69 in Shanghai at the end of 2009, and spent much of the season nursing a groin injury. If fully recovered, he may be closer to Bolt than many think, and if Bolt is not quite at 100%, Gay may well take the win at least once this year.

On the women's side, Tirunesh Dibaba has a 2009 to forget, hampered by injury and poor form, and she'll be one to watch. I'd pick her to bag a world record in the 5,000m, and be the dominant distance runner of 2010. In the sprints, Carmelita Jeter ended 2009 running faster than any woman since Marion Jones (we all know how that ended), and it will be interesting to see if she can replicate that in 2010, against the usual combination of Carribean islanders, particularly Shelly-Ann Fraser from Jamaica.

The Commonwealth Games - finding meaning among the "what ifs"

The other big global event of the year (aside from the Winter Olympics) is the Commonwealth Games, in Delhi, in October. The Commonwealth Games are always a little tricky to interpret or pin down, because in the absence of the USA, South America, Asia and most of Europe, they lack the depth and quality of performance in most events. Yet they are still one of the largest multi-sports events in the world, and for the nations competing, remain a focal point of the calendar (though for different reasons).

There are some events where the quality is equal to that of the Olympics or World Cups - Rugby Sevens, for example, has long had the Commonwealth Games as its showpiece tournament, and with New Zealand, Fiji, England, Kenya, Australia, South Africa, and Samoa all competing with their strongest teams, the Commonwealth title at rugby sevens is equal in quality to the pinnacle of the sport. The same cannot be said for track and field, or swimming.

The absence of the USA makes sprint events much weaker, and Jamaica tends to send second-tier sprinters (not sure if this will happen in 2010). The field events, normally dominated by European nations, are considerably weaker, and the distance events have no Ethiopian threat, and Kenya tends to send its junior, second tier athletes. For swimming, no USA, no China, no France or Japan or eastern European nations means much the same thing.

So October is likely to produce a confusing mixture of excitement and congratulations, but an empty feeling of "what if" for many medal winners, depending on the event (if looked at objectively - those who win always disagree).

Back in 2006, I analysed the performances that won Commonwealth medals (in Melbourne, 2006), and found that they were only 85% to 90% of the level that was required to win medals in the preceding Olympic Games (Athens, 2004). In other words, you can produce an 85% effort and be Commonwealth champion (and that's two years later). This was true for swimming and track and field.

What the Commonwealth Games CAN be is a great platform for Olympic preparation, and provided the coaches and sports administrators understand the context of performance, they are valuable as part of the process towards 2012. However, those who decide they are world-beaters having beaten only the second level of competition miss this chance and end up falling further behind the rest of the world in subsequent years.

That should produce some discussion at the end of the year.

Football (or soccer, if you wish) - the World Cup comes to South Africa

And then finally, how can I not mention the 2010 FIFA World Cup, which happens right here in South Africa in June/July? The biggest single sporting event on the planet, the World Cup will stop South Africa for a month. Already, the buzz is huge, the country expectant and giddily optimistic. I'm sure it will be a success - FIFA would not allow it not to be, to be honest, even if it means stage managing everything.

Unfortunately, the global football year has gotten off to a terrible, tragic start, with the attack on a Togo team bus in Angola claiming the lives of two men linked to the team - an assistant coach and a spokesman. The bus was traveling through Angola, where the African Cup of Nations takes place this month, when gunmen opened fire. There were reports, now being denied, that Togo had withdrawn from the tournament (one can hardly blame them), and other teams questioning whether sport is worth that much risk. It clearly is not, and the issue of safety in sport is going to be a big one in 2010, particularly around the Commonwealth Games, described above, in India.

Also unfortunately, many have asked questions of Africa's capabilities of hosting the World Cup as a result of this incident. I must stress that this is a completely unrelated event, that while tragic, should have no bearing at all on South Africa's capacity to host the 2010 World Cup in June. However, the local committee have had to respond and provide assurances as a result, and in a way, they are 'victims' of their own promotional campaign.

I heard a spokesman for the 2010 World Cup saying that he didn't understand why people were linking the events in Angola with South Africa. The simple answer is that we've designed it that way - all the talk leading up to 2010 has been that South Africa is merely the stage, but the 2010 World Cup belongs to the African continent. The organizing committee have been (too) quick to point out that this is Africa's time, Africa's tournament. So, when the tragic events unfolded in Angola, it was inevitable that people would link them to South Africa - we basically told the world to do this in anticipation. Sadly, the world listened. Again, however, those events will have no bearing on the World Cup in SA.

The science of football - our focus

What will have a bearing, or at least, will be discussed, is the science of football performance, including the impact of altitude on football matches. South Africa is one of the few countries in the world that can host high altitude sports events (2000m) only a few hours away from sea-level competition. As a result, teams who play at the coast and then have a match at altitude have the eternal problem of how to adapt to the reduced air pressure and oxygen availability.

I am actually presenting on this topic at the ILSI International Conference on Nutrition and Hydration in Football, in Johannesburg in April this year. My topic is Altitude and football, but the programme includes some well-known researchers in their fields, including Louise Burke (a reader of the site - thanks Louise - speaking on travel and performance), Ron Maughan, and Prof Tim Noakes (speaking on heat and football). It should be very interesting and will hopefully throw up some great discussion which I'll cover here on the site. There is a lot of science in football, ranging from injuries to performance to the physiology of elite football players, and given that the World Cup is right here, June will be a good time to cover some of that!

In closing - a very busy year

So that's only four sports to look forward to, with only their surfaces scratched. There's also cycling, the Tour de France with Contador against Armstrong (which is much like 2009, except this year they'll race against each other, not fling accusations in the media and undermine team leadership on Twitter), plenty of doping I am sure, in all sports.

Doping is a guaranteed topic of discussion in sports, unfortunately. Perhaps, for the first time, even in boxing, which, until Floyd Mayweather brought it up, had zero interest in doping control. As someone who follows cycling and running, I find the argument over doing doping controls 14 days before a fight absolutely hilarious, and damaging to the sport. Boxing should be ashamed of its policies if a request to implement WADA policies is met with such indignation, and all boxers and officials should ask how thousands of sportsmen subject themselves to testing the day of competition, in the middle of stage races, and accept it as part of the requirement to achieve clean competition. I can only assume that clean competition has never been a concern for the sport.

In the interests of time, I'll stop there. The crystal ball can't see that much anyway. Tomorrow, I'll do a brief post just covering one or two ideas for series in 2010, topics of interest and science that can be applied to your training. We're always looking to improve on our content and style of the site, and so we'll introduce some of that tomorrow.

Jonathan Dugas, PhDCurrent residence:Chicago, USAEmployment: Director of Clinical Development, The Vitality GroupResearch interests: Temperature regulation and exercise performance, with a special emphasis on how fluid ingestion affects those two things. In addition, the effects of exercise on health improvement and risk modification in large populationsSports interests: Cycling, running, triathlon, endurance sports

Full discolusre:The views expressed on this site are not those of the University of Cape Town (UCT), the Sports Science Institute of SA (SSISA), The Vitality Group, or Discovery Holdings.